Add MTP_OBJECT_ID column name to MediaStore.MediaColumns

This column will be added to the images, audio_meta, video and audio_playlist
tables to cross reference to the MTP objects table.

Renamed MTP_OBJECT_HANDLE (which is used only by the media scanner) to
MEDIA_SCANNER_NEW_OBJECT_ID to avoid confusion.

Change-Id: I8093485dc0438f408a505e82ffddd0710c7a512c
Signed-off-by: Mike Lockwood <lockwood@android.com>